Gas blast circuit breaker with nozzle formed contacts and control for associated gasoutlet valves



March 21, 1967 P. BALTENSPERGER 3,310,648

GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTS AND CONTROL FORASSOCIATED GAS OUTLET VALVES Filed Aug. 15, 1964 2 Sheets-Sheet 1 PauLBalfnsperger 13% 1% Y9 JPWIW ATTORNEYS P. BALTENSPERGER 3,310,648

March 21, 1967 GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTS ANDCONTROL FOR ASSOCIATED GAS OUTLET VALVES Filed Aug. 13, 1964 2Sheets-Sheet 2 I&W/

INVENTOR Pcw L Baliensperge r /fiw iigguvgpwwaw ATTORNEY S United StatesPatent 3,310,648 GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTSAND CONTROL FOR AS- SOCIATED GAS OUTLET VALVES Paul Baltensperger,Wurenlos, Switzerland, assignor to Aktiengesellschaft Brown, Boveri &Cie., Baden, Switzerland, a joint-stock comp-any Filed Aug. 13, 1964,Ser. No. 389,345 Claims priority, application Switzerland, Sept. 20,1963, 11,609/63 7 Claims. (Cl. 200148) This invention relates to apreferably multi-break gas blast circuit breaker comprisingtwin-nozzle-contact interrupter chambers which are at high tension andpres surized by a compressed gas in both make and break positions, eachnozzle contact being associated with an outlet valve for the generationof air blast for controlling the arc and one of said outlet valves beingoperable by actuator means at earth potential.

Air blast circuit breakers are known in which the interrupter unitcomprises two nozzle contacts. The pair of nozzle contacts in thiscircuit breaker is located inside an interrupter chamber which remainspermanently under gas pressure. When the circuit breaker is tripped thenozzle contacts are separated by either one or both being withdrawn byappropriate actuating means and the resultant arc is controlled by anair blast. For this purpose each of the nozzle contacts is associatedwith an outlet valve which remains closed so long as the circuit breakeris closed, but which opens for a brief period when the nozzle contactsseparate, permitting the compressed gas in the interrupter chamber toescape through the interior of the nozzle contacts, thereby creating anair blast for controlling the are within the contact gap. The outletvalves may be pneumatically or hydraulically controlled in such mannerthat one of the outlet valves is operable by actuator means which are atearth potential, whereas, the other outlet valve is pneumatically orhydraulically operable through an insulating tube. When the circuitbreaker is open, the insulating tube is at high potential and thisintroduces the familiar problems involved in controlling the creepcurrents. These are particularly difiicult to control in circuitbreakers for rated voltages across each break which are relatively high,for example, in the order of llO kv. and more. 7

The object of the present invention is to provide a solution permittingthe said difficulties to be overcome. According to the invention, thisis achieved by operating the other outlet valve by an insulatingtransmission member, which is associated inside the interrupter chamber,with actuating means and which only briefly makes contact with thecontrolled outlet valve, being otherwise separated therefrom by acompressed gas gap.

An embodiment of the proposed circuit breaker will be described ingreater detail by reference to the accompanying drawings in which FIG. 1is a part sectional view of one interrupter chamber of a twin-breakpneumatic air blast circuit breaker according to the invention, whereasFIG. 2 is a section taken on the line I-I in FIG. 1, and

FIG. 3 is a section taken on the line II-II in FIG. 2.

FIG. 1 shows a hollow post type insulator 1 which supports the circuitbreaker casing 2. Thelatter comprises a central portion 3 which isfirmly connected on each side to an interrupter unit 4 containing acompressed gas. 5 is a movable nozzle contact formed with a pistonportion 5a working in a cylindrical extension 3a of the central part 3of the casing. The current is taken through a sliding tulip connector 6screwed to extension 3a by a cover plate 7. 8 is a spring interposedbetween .vided with openings 45a.

3,310,648 Patented Mar. 21, 1967 piston 5a and the interior of extension3a. The center portion of the casing is surmounted by a valve box 9closed at the top by a cover 10. An insulating push rod 11 which axiallytraverses the post insulator 1 extends upwards through the centerportion 3 of the casing and at the top carries a hollow valve stem 12with openings 12a. This hollow valve stem 12 carries valve discs 13 and14. Valve disc 13 cooperates with two seals 15 and 16, whereas, valvedisc 14 similarly cooperates with two seals 17 and 18. The seals 15 and1-8 are countersunk in plates provided with openings 19 and 20respectively. The interior of the valve box 9 communicates with theoutside through holes 21. An air pipe 22 leads to the piston chamber 24on the left of piston 5a, and a second air pipe 23 leads to the chamber25 on the right of the piston. A channel 26 provides a. communicationbetween pipe 22 and a cylinder 27 containing a piston 28. Piston 28contains an opening 29 connecting channel 26 with chamber 30. Thischamber is closed by a cover 31 which slidably guides an insulating pushrod 32 firmly secured to piston 28. 33 is a spring interposed betweencover 31 and piston 28. The left hand end of the insulating push rod 32has a widened head 32a. Secured to the left hand end of interrupterchamber 2 is an insulating bushing 34 inside which a hollow conductor 35is supported by an insulating sleeve 36. Hollow conductor 35 is rigidlyattached to an intermediate member 37. The latter carries a cylinder 38containing a sleeveshaped valve element 39 which is slidably guided inthe cylinder by its piston 39a. The latter is traversed by a hole 3911which connects the two valve chambers 40 and 41. Located in chamber 41is a spring 42. This is interposed between piston 39a and theintermediate member 37. The interior of the hollow conductor 35 is inpermanent communication with the outside atmosphere through an openingat its left hand end not especially shown in the drawing. Attached tocylinder 38 is a stationary nozzle contact 43. The left hand end of thisnozzle contact is widened and encloses a valve-seat 43b which issupported by web members 43a and which is provided with an inserted seal44. Cylinder 38 also supports the valve casing 45 of a valve member 46.The latter is formed with a piston 46a which bears against one end of aspring 47 of which the other end is supported by the valve casing cover48. An opening 48a in the cover provides permanent communication betweenchamber 49 and the interior of the interrupter chamber 2. The righthandend of valve member 46 carries a tappet 50 projecting from valvecasing 45 which is also pro- Chamber 51 communicates on the one handthrough channel 52 with chamber 40 and on the other hand through gap 53with chamber 54. From gap 53 an air pipe 55 leads to the interior of theintermediate member 37. 56 is a seating seal cooperating with valvemember 46 in valve casing 45. The actuating gear which is at earthpotential is shown at the bottom end of push rod 11. This comprises acylinder 57 slidably containing a piston 58 to which push rod 11 isattached. The two interrupter chambers 2 are completely symmetrical sothat a representation in the drawing of the right hand half of thecasing is not considered necessary. The interrupter casing is filledwith compressed gas through the hollow post insulator 1, the openings 3bin the central portion of the casing ensuring that both halves of thecasing are equally filled. The two chambers 60 in the center portion 3are in communication through a chamber 60a as will be readily seen byreference to FIGS. 2 and 3. The same reference numbers are used for likeparts in FIG. 2 as in FIG. 1, FIG. 2 being a part section taken on theline I-I in FIG. 1 through the center portion 3 of the casing. FIG. 2further shows a cylindrical casing 61 which is firmly inserted into thecenter portion 3 and which contains a valve member 62. A valve closingspring 63 is interposed between parts 61 and 62. The valve member 62cooperates with a sealing disc 64 inserted in the center portion 3.Valve casing 9 is connected on the one hand by air pipe 65 to chamber66, a throttling constriction 67 being provided at the point of entryinto chamber 66, and on the other hand by an air pipe 68 to chamber 69.FIG. 3 is a view from below of a section taken on the line II-II in FIG.2. In this drawing parts corresponding to those shown in FIGS. 1 and 2are again identified by the same reference numbers.

The described arrangement functions as follows:

For operating the circuit breaker, compressed gas is admitted throughadmission pipe 59 into the chamber above piston 58 in cylinder 57,causing the piston to descend. The piston simultaneously withdraws theinsulating push rod 11 together with the hollow valve stem 12, so thatboth valve discs 13 and 14 are moved downwards until they seat on thevalve seals 16 and 18 respectively. Consequently, chamber 25 is nowplaced into communication with the outside atmosphere through pipe 23and holes 21 and at the same time chamber 24 is filled through pipe 22with compressed air from the interrupter chamber 2 and the postinsulator 1 entering through openings 12a, the hollow valve stem 12 andopenings 19. The effect of the compressed gas in chamber 24 is todisplace piston a and hence, the movable nozzle contact 5 against theresistance of spring 8 into circuit breaking position. At substantiallythe same time, compressed gas is also applied through channel 26 to theright hand face of piston 28, forcing the same together with theinsulating push rod 32 to the left against the resistance of spring 33.The head 32a of the insulating push rod strikes tappet 50 and pushesvalve member 46 to the left, thereby admitting compressed gas throughthe holes 45a and channel 52 into chamber 40. Piston 39a and hence valvemember 39 are therefore displaced to the left against the resistance ofspring 42 and valve member 39 is lifted off its seal 44. The are whichnow strikes between the separating nozzle contacts 5 and 43 is exposedto the blast of the gas entering the fixed nozzle 43 and escaping to theoutside air through the interior of parts 43, 39 and 35. At the sametime the interior of nozzle contact 5 is likewise placed intocommunication with the outside air, so that the arc is exposed to adouble blast. The chambers 60 with which the interior of the two valvenozzles 5 communicate are exhausted because the downward displacement ofthe valve discs 13 and 14 has caused pipe 65 (FIG. 2) to fill withcompressed gas and pipe 68 to be placed into communication with theoutside. Owing to the presence of the throttling constriction 67 at theend of pipe 65 chamber 69 can at once exhaust through pipe 63, Whereas,chamber 66 is only gradually filled. Consequently, the rising pressurein chambers 60, 60a lifts valve member 62 off its seal 64, permittingcompressed gas to escape from chambers 60, 60a to the outside. As willbe understood from FIGS. 2 and 3 the outlet valve (62, 64) is common toboth the central nozzle contacts 5 of the twin break interrupter gear.At the end of a given period of time which is sufficient for the arc tobe safely extinguished, the blast in the open circuit breaker gap (5,43) ceases. This is due to the fact that chamber 66 has meanwhile beenfilled with compressed gas through constriction 67 sufficiently forreturning valve member 62 into the position shown in FIGS. 2 and 3 withthe assistance of the valve closing spring 63. chamber 30 (FIG. 1) haslikewise meanwhile sufiiciently filled with compressed gas through hole29 in piston 28 to permit the power of spring 33 to restore piston 28and hence, the insulating push rod 32 to the right. Tappet 50 is thusreleased and spring 47 can push valve member 46 back to the right intocontact with its seating seal 56.

On the other hand 4 Chamber 40 can therefore exhaust through channel 52,gap 53, pipe 55 and the interior of parts 37 and 35 to the outside air,and spring 42, assisted by the compressed gas which is able gradually toenter chamber 41 through aperture 3% in piston 39a, is thus able torestore valve member 39 into the illustrated position. When the circuitbreaker is stationary in the break position there is therefore nocontact between the insulating push rod 32, 32a and the tappet 50 whichis at opposite potential. The intervening gap is filled with compressedgas and prevents current creep along the insulating push rod 32.

For closing the air blast circuit breaker, the chamber above piston 58in cylinder 57 is exhausted through pipe 59. The compressed gas actingon the underside of valve disc 14 through opening 20 can therefore raisevalve disc 14 and hence, parts 58, 11, 12 and 13 into the illustratedpositions. Chamber 24 exhausts through pipe 22 and chamber 25 refillswith compressed gas through pipe 23. Piston 5a and hence nozzle contact5, assisted by spring 8, are therefore returned into the make, i.e., theclosed contact position shown in the drawing. During this operation theinsulating push rod 32 remains stationary. However, chamber 30 exhauststhrough aperture 29', channel 26 and pipe 22 in readiness for a repeatedoperation of the circuit breaker.

Outlet valve 62, 64 (FIGS. 2 and 3) remains closed since chamber 69fills with compressed gas through pipe 68 more quickly than chamber 66can exhaust through constriction 67 and pipe 65.

I claim:

1. In an electrical circuit breaker of the gas blast type, thecombination comprising a casing forming therein an interruption chamberwhich is gas-pressurized and at a high potential, a pair of nozzle typecontact members located in said interruption chamber, a normally closedoutlet valve individual to and which serves when opened to place theinterior of each said nozzle contact member in communication with theopen air exteriorly of said casing, first actuating means at earthpotential for actuating one of said contact members to effect itsdisengagement from the other contact member and to simultaneously opensaid outlet valve correlated to said actuated contact member, and saidsecond actuating means for operating the other outlet valve correlatedto said other contact member to its open position upon disengagement ofsaid contact members, said second actuating means including a drivingmember of insulating material and a member driven thereby whose movementcontrols opening and closing of said other outlet valve, said drivingand driven members being located in said interruption chamber and beingnormally maintained in spaced rela tion to thereby establish agas-pressurized insulating gap therebetween, and means controllingmovement of said driving member by operation of said first actuatingmeans to effect a brief driving engagement as between said driv-' ingand driven members thereby to effect a brief opening of said otheroutlet valve.

2. An electrical circuit breaker as defined in claim 1 and which furtherincludes means mounting said outlet valve correlated to said secondactuating means interiorly of said interruption chamber, and whichfurther includes an insulating bushing through which are conducted theexhaust gases passing through said outlet valve.

3. An electrical circuit breaker as defined in claim 1 wherein saiddriving member of said second actuating means is constituted by a pushrod made from insulating material and which is mounted for movementlongitudinally of itself against the action of a biasing spring toengage said driven member which is constituted by a tappet on said otheroutlet valve.

4. An electrical circuit breaker as defined in claim 1 wherein saidother outlet valve correlated to said second actuating means comprises amain valve cylinder mounted in said interruption chamber, a main valvepiston within said valve cylinder and which is slidable against theaction of a biasing spring to open said outlet valve, and a servo valvefor supplying pressurized gas into said main valve cylinder, said servovalve including a cylinder and control piston therein, and said controlpiston of said servo valve being connected to said driven member of saidsecond actuating means.

5. An electrical circuit breaker as defined in claim 4 wherein said mainvalve cylinder is located concentric with and adjacent to the correlatednozzle contact member and said main valve piston is hollow and serves topass through it the gases discharged through said nozzle contact member.

6. An electrical circuit breaker as defined in claim 1 wherein saidmeans controlling movement of said driving member of said secondactuating means is constituted by a spring biased piston located withina cylinder disposed within said interruption chamber, pressurized gasbeing admitted into said cylinder simultaneously with admission ofpressurized gas into a cylinder to actuate a piston connected to one ofsaid nozzle contact members and which constitutes the said actuatingmeans therefor.

7. An electrical circuit breaker as defined in claim 1 wherein saidoutlet valve correlated to said second actuating means comprises a mainvalve cylinder mounted in said interruption chamber, a main valve pistonWithin said valve cylinder and which is slidable against the action of abiasing spring to open said outlet valve, and a servo valve forsupplying pressurized gas into said main valve cylinder, said servovalve including a cylinder and control piston therein also within saidinterruption chamber, said control piston of said servo valve beingconnected to said driven member of said second actuating means, saidmeans controlling movement of said driving member of said secondactuating means including a control cylinder likewise mounted in saidinterruption chamber and a spring biased piston located Within saidcontrol cylinder and attached to said driving member, pressurized gasbeing admitted into said control cylinder simultaneously with admissionof pressurized gas into a cylinder to actuate a piston connected to oneof said nozzle contact members and which constitutes the said actuatingmeans therefor.

1. IN AN ELECTRICAL CIRCUIT BREAKER OF THE GAS BLAST TYPE, THECOMBINATION COMPRISING A CASING FORMING THEREIN AN INTERRUPTION CHAMBERWHICH IS GAS-PRESSURIZED AND AT A HIGH POTENTIAL, A PAIR OF NOZZLE TYPECONTACT MEMBERS LOCATED IN SAID INTERRUPTION CHAMBER, A NORMALLY CLOSEDOUTLET VALVE INDIVIDUAL TO AND WHICH SERVES WHEN OPENED TO PLACE THEINTERIOR OF EACH SAID NOZZLE CONTACT MEMBER IN COMMUNICATION WITH THEOPEN AIR EXTERIORLY OF SAID CASING, FIRST ACTUATING MEANS AT EARTHPOTENTIAL FOR ACTUATING ONE OF SAID CONTACT MEMBERS TO EFFECT ITSDISENGAGEMENT FROM THE OTHER CONTACT MEMBER AND TO SIMULTANEOUSLY OPENSAID OUTLET VALVE CORRELATED TO SAID ACTUATED CONTACT MEMBER, AND SAIDSECOND ACTUATING MEANS FOR OPERATING THE OTHER OUTLET VALVE CORRELATEDTO SAID OTHER CONTACT MEMBER TO ITS OPEN POSITION UPON DISENGAGEMENT OFSAID CONTACT MEMBERS, SAID SECOND ACTUATING MEANS INCLUDING A DRIVINGMEMBER OF INSULATING MATERIAL AND A MEMBER DRIVEN THEREBY WHOSE MOVEMENTCONTROLS OPENING AND CLOSING OF SAID OTHER OUTLET VALVE, SAID DRIVINGAND DRIVEN MEMBERS BEING LOCATED IN SAID INTERRUPTION CHAMBER AND BEINGNORMALLY MAINTAINED IN SPACED RELATION TO THEREBY ESTABLISH AGAS-PRESSURIZED INSULATING GAP THEREBETWEEN, AND MEANS CONTROLLINGMOVEMENT OF SAID DRIVING MEMBER BY OPERATION OF SAID FIRST ACTUATINGMEANS TO EFFECT A BRIEF DRIVING ENGAGEMENT AS BETWEEN SAID DRIVING ANDDRIVEN MEMBERS THEREBY TO EFFECT A BRIEF OPENING OF SAID OTHER OUTLETVALVE.